The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
A pumping unit is a kind of conventional equipment in the oil field. Two exemplary known alternative configurations for pumping units include a beam-pumping unit and a vertical pumping unit.
Beam-pumping units have been widely used throughout the oil industry, which due to its simple structure, long service life, and over one hundred years of use. Beam-pumping units include a beam pivoted near a center, a motor providing power to stroke one side of the beam up and down, and the other side of the beam being attached to pump machinery. Beam-pumping units include low efficiency and high energy consumption operation. Stroke length and stroke frequency tend to be inflexible. Adjusting an output of a beam-pumping unit requires significant adjustments to the unit and the maximum output of the unit can be insufficient to meet large load requirements.
Vertical pumping units have been used in recent years. Vertical pumping units can include mechanical reversing and motor reversing mechanisms. A stroke length of the mechanical reversing mechanism of known mechanisms is fixed and stroke frequency is also difficult to adjust. Known vertical pumping unit configurations cannot adapt to different requirements under various working conditions.
Known vertical pumping units, including mechanical reversing mechanisms, include complicated mechanical structures. Such known mechanical reversing mechanisms, including moving mechanical parts under significant stress, increase maintenance workload.
Mechanical transmissions used in known vertical pumping units are complex. The transmission includes many flexible components and it has poor reliability, reversing radius is small, loaded shocking is large, and failure rates are high. An expected useful life for a vertical pumping unit can be significantly less than an expected useful life for a typical beam-pumping unit. Many vertical pumping units are designed and marketed only to prove to be unusable in the field.